I second this, being able to store the .rev and .riv files locally, as well as render on-device can be valuable. When I first used Rive it kept crashing and wouldn’t auto-save no matter how much I refreshed, so I kept losing hours of work. Thankfully that hasn’t happened since, but not being dependent on an internet connection would help.
(From what I can tell, Rive uses Flutter, which has beta support for desktop apps. So while it’s possible to start working on this today, we shouldn’t expect it to be finished until after Flutter finalizes their desktop support.)